How do you calculate the 'Capital stock at the end of the year' with the following information?

Revenues: $375,000
Expenses: $297,000
Net Income: $78,000
Retained earnings at the beginning of the year: 0
Retained earnings at the end of the year: $68,000
Liabilities at the end of the year: $225,000
Assets at the end of the year: $393,000